Slack-adjuster.



s., P. eoMBLLA. sLAK AmusTrm. APPLICATION FILED JULY 18, 1912.

Patented Dec.3,1912.

2 SHEETS-'SHEET l.

S. AI.-(=f0l\/IELLA. "'SLAGKADJUSTBR.-

A?PLI'okfnon FILED JULY 1s, 1912. v

, Patented Dec; 3. ,1912.

2 sHBETwsHaEM.

@massa ruin STES PAT sLAoK-ADJUSTER.

heisses.

Specification ofy Letters Patent.

i comiected system of rods and levers, to force the brake shoes against the Wheels. As the brake shoes wear down, and the brake. rigging becomes stretched, the .brake piston must necessarily travel farther in its cylinvder in order to bring the shoes up to the wheels, and since 'the air brake system is designed to give certain cylinder pressures for a given constant travel of the brake piston, it is important that the :so-called slack,

produced by wear in the brake shoes and,y

rigging, be taken up, in order to maintain stantialy constant travel of the brake pisl ,in and an eiicient and satisfactory braking pressure.

Various forms of automatic slack adjustces have been designed for this purpose, and thecbject ot' my invention is to provide an improved device of this character, which shall be simple in construction, durable and etlicientl in operation, requiring very ,little attention for maintenance, and adapted for use with power or hand brakes on either 'freight or passenger cars.

ln the accompanying drawings: Figure l is a side elevation of a slack adjusting de- ,vicc embodying my improvement, the xed support forthe ratchetwheel beingindicated in vertical section; Fig. 2. a transverse section taken on the. line :1i-fc o 1; Fig. 3, a viewI similar to ing a slight moditication; l: d l verse 'section of `the-samertaken on the 1/-2/ of Fig. 3: Fig t. a detail vieux-stmwing a modified form ot helical surface; 6, a longitudinal section showing a n'ioditi.- cation of my improvement, as applied to the piston rod of the brake cylinder; Fig. an end, view of the same; and Fig. 8., a sectional view similar to Fig. t3, but showing a modified form of piston rod.

My improvement may be applied in con nection with any movable member of the brake rigging, such as the brake piston rod,

the connection as the wear takes place,v

while in the case of a compression rod, the adjustment would be made to lengthen the connection. ln either case. the rod coperaties with a pavvl and ratchet. mechanism, which is mounted in a fixed or stationary position relative to the longitudinal movement of the rod and engages with the latter through a helical surface having the movement with the rod in such afinanner that the longitudinal movement of thevrod and this surface in one direction 'causes the ratchet Wheel to rotate, and if the length of movement o r travel is suilicient to turn the ratchet wheel sutiiciently ,to permitthe -pawl to drop into the next notch of the. ratchet Wheel, it is held against. turning on the back vstroke thereby @arising the rod to rotate the screw connection to take up slack during the return or release movement of the rod produced by the usual release springs. it' ratchet Wheel `has the teeth in opposite direction the rotation of screw connection willbe durin the direct movement when the a lication of brake takes place. f

As shown in Figs. l and 2 ota the drawing, the movable member or rod, 1, of the brake rigging is provided with a screw connection, 3, to an attached lever block or to another section of the rod, and a portion of the rod is provided with one or more helical suriaces,` 6. four such surfaces being shown, making the section of this-portion of the rod square. This portion of the member or rod having the helical surface extends through a correspondingly shaped' opening in the cen- 'ter of the ratchet wheel, 2, which `is rotataf' mounted upon Aa fixed support` 5, to which is Ialso pivoted the pawl, 4, for enthe teeth or" the ratchet wheel. The support, 5, may be fastened to the car frame work, or to the truck frame, or to any convenient object.

lWhen the brakes are applied. thelrod or member moves in one direction, for instance, toward the lett, and the curlved portion hav"- ing thahelical surface sliding the1 h the ratchet wheel rotates the. same infthetien ot the arrow, Fig. 27 endif the latontod Dec. 3, ittff Application tiledV July 18. 1912. Serial No. 710,164.

i'i o nientaiid Iconsequently the rotation, 4is sufficient for the pawl, 4, to fall. into the next notch, it is plain that the rod'will be rotated upon the return movement bymeans.l

of the cam surface,I thereby adjusting the .sciew'` connection to take up the slack and maintain the brake piston travel substantially constant.' The. pit-ch of the cam sur-- `face is properly designed so: that the ratchet wheel will be rotated one or more notches when the piston travel becomes excessive due to .wear of vthe brake shdes and rigging..

If the travel is not sufficient lto advance the paivl one notch upon the ratchet teeth, the? wheel simply rotatesy a distance less than one notch' on the outward movement, and back again" upon the reverse movement without turningtlie-screw coniiectijom'as will lbe'l readily understood. The pawl may beheld j down bygravity or by a spring in the usual manner and mayberaised out of engagement with the ratchetteeth when it isdesiredto turn the wheel and rod forv reset- 'ting the screw at' the time new brake shoes" are inserted. y l

In thel construction illust-rated in Figs. 3

.and 4', themovable member, 1, is shown in I the form of a hollow rod or sleeve having a threaded or screw connection, '3, at eachend with other sectionsA of the rod, the'helical surfaces being formed upon the exterior of wheel.

the sleeve whichI extends through the ratchet- The operation of this form of the device is the sa'me 'as that before described. except that the screw connection is adjusted at both ends of the sleeve vinstead of at one point only.

The helical surface by which the ratchet through the fixed ratchet wheel, which is mounted to rotate upon the Anon-pressure head` 7. of the brake cylinder, the pawl,4,

'alsovbeing pivoted to the cylinder head as shown. The piston rod may be eitlierrigid with the piston, as shown in Fig.v 6, or may preferably be mounted so as lto have a rotary movement relative thereto as shown in Fig. v8.

The slack adjusters herein described can operate inthe opposite direction, that is,

.when brake is applying, but in this case the ratchet wheel 2., in Figs. l to 8, must be so .adjusted as to have the teeth inthe opposite direction.

ratchet wheel (and n will now be geen ha in au if 'aie medi;

fications the movable member'orrod has av longitudinal movement; ,relativel the engages therewith through a helical surface which produces 'a/ 70 rotation of the wheel tol-a succeeding notch ofthe pawl upon the outward n i'ovem'ent,-

and a rotation of the r'odzto adjust the screw connection land take up the slack `upon` the l return or release movement of the brake ri ging or upon direct movement of. the-bral e rigging, when thebra'ke is applying.

I anu aware. that prior to my invention slack 'adjusters' haver been made with a mov.- ,l

able ratchet wheel. and a fixed cam surface,l

which adjusted the slack on part of the pis-v ton travel, and 4I therefore .do not claim such combination.

Having now .described 'inyinventiom what I claim asnew and desire to secure by yLetters Patent is:l 'g 1. In anlautomatic Aslack adjuster, the

combination with a movable member' of the.

brake rigging having a screw connectionand,

.a helical surface, of'a pawl and ratchet :wheel fixed relative to longitudinal movement of said member and having an opening engaging the' helical. surface to rotate the ratchet wheel and screw connection; l

2. In an automatic slack adjuster, the

.combination with a movable member of the brake rigging having a screwconnection, of. I

a 'ratchet mechanism, the member having af longitudinal movement in the ratchet wheel, and one of said parts being provided withv a sliding .helical surface for rotating said-v screw connection and ratchet wheel.'

3. In an automat-ie slack adjuster, the combination with a ratchetmechanism,I of'a member of the brake rigging having a AScrew connection and .a longitudinal movement rell ative to the ratchet wheel. said parts being'.

provided withengaging slidinghelical siir-Y faces adapted to rotate said screwV connection and ratchet wheel.l

combination with a movable member of the brake rigging. of a pawl and rotatively fixed ratchet wheel, said member and ratchet wheel having engaging A'sliding surfaces adapted torotate the ratchet wheel when the member moves in one direction, and to ro- 1510 e. In an' automatic slack adjuster,. the' tate the screw connection when the member l moves in the opposite direction.

5. In an automatic slack adjus'teip't-hev combination with a movable member ofthe brake rigging having a screw connection, of a lpaWl and ratchetwheel rotatively fixed on a support, said parts having'coperating sliding helical surfaces adaptedto cause a rotation of the ratchet wheel by thelongitw dinal movement of the brake rigging meinber. I

6. In an automatic slack adjuster, the

' combination with a movable member of the brake rigglng having a screw connection, of a'pawl and ratchet wheel mounted on a stai tlonary support, 'said member extending .through the ratchet Wheel and provided Withl asliding helical surfacev for rotatingv 'said wh'eel.`

47. 4In van automatic slack adjuster, the combination 'witha-rodhaving a screw con.- necti'on movable with the brake rigging, of a pawl and ratchet Wheel mounted ona fixed support, said rody extending' through the ratchetI wheel and provided with a sliding helical surfacel engaging acorresponding surfacein the opening through said wheel.

'8. In an 'automatic' slack adjuster, A the combination with'the brake piston rod having a screwV connectiom Qfa pa'wl and'ratchet Wheel -mounted ont'he brake cylinder, Islaid rod extending through 'theatthe't-whene and having a sliding' helical `surface engaging' therewith. l

9. In an automatic slack adjuster, the combination with a brake cylinderz and pis-l t0n rod having a screw connection, ofl a ratchet wheel rotatably mounted'on the cylnder,' the piston rod extending through the ratchet'wheel and engaging therewith by a sliding helical sur ace to cause' the rotation of said ratchet wheel by the' longitudinal movement of. the rod.'

10'. In an automatic slack ad'uster7 the combination with mounted on the cylinder, and a pawl also pivoted vupon the cylinder, the piston rod being provided with a sliding helical surface and extending through said ratchet wheel.

In testimony whereof I have hereunto setbrake cylin er, piston and rod, .the rod ,eing rotatably mounted` relative to the piston,and havinga screw connection, of a ratchet Wheel lrotatably-35k 

